The subject matter disclosed herein relates generally to magnetic resonance imaging systems and, more particularly, to cooling and electrically separating two or more gradient coils for magnetic resonance imaging systems.
Magnetic resonance imaging (MRI) systems enable imaging based on a primary magnetic field, a radio frequency (RF) pulse, and time-varying magnetic gradient fields that interact with specific nuclear components in an object, such as hydrogen nuclei in water molecules. The magnetic moments of such nuclear components may attempt to align with the primary magnetic field, but subsequently precess at a characteristic frequency known as the Larmor frequency. An RF pulse at or near the Larmor frequency of such nuclear components may cause the magnetic moments to be rotated. When the RF pulse has ended, the magnetic moments may attempt to realign with the primary magnetic field, emitting a detectable signal.
At least three discrete gradient coils (x, y, and z) may produce time-varying magnetic gradient fields (Gx, Gy, and Gz) calculated to enable detection of signals from a specified slice of the object. Because the gradient coils may be disposed near to one another, a partial discharge of voltage may occasionally occur between two of the gradient coils, which may cause any images then being acquired to display one or more artifacts. To prevent partial discharge, each generally cylindrical gradient coil may be electrically separated from the other by a glass-filled, epoxy-based resin. Such an epoxy-based material may have many drawbacks, including low partial discharge inception voltage (PDIV) characteristics, inefficient gradient coil cooling, and long manufacturing cycles due to the vacuum pressure impregnation procedure generally employed in the manufacture of epoxy-based gradient coils.